Agricultural irrigation systems typically utilize water distribution lines, typically fashioned from plastic tubing, to distribute water to the plants. A distribution water line will usually have a number of sections of irrigation tubing branching off of the main water line, where each section of irrigation tubing typically has an emitter on its distal end. Each of these sections of tubing are connected to the main line by a coupler, where one end of the coupler is inserted through the wall of the main line and the other end is inserted into an open end of the section of tubing.
The installation procedure can be time consuming and result in less than satisfactory results. First, it is typical to punch a hole through the plastic distribution line with a tool which displaces the wall material to make an opening. Depending on the type of tool, wall material is displaced in the process and leaves a lip of material around the inside edge of the opening. This lip of material can interfere with the seal formed between the coupler and the wall of the distribution line, leading to water leakage around the coupler.
The second problem pertains to the insertion of a first end of the coupler into the open end of the irrigation tubing. The coupler is attached to the irrigation tubing by an interference fit between the outside diameter of the first end of the coupler and the inside diameter of the tubing, where the tubing wall is stretched to fit around the first end of the coupler. Each end of the coupler will typically have a conical configuration, where the diameter progressively gets larger from the end of the coupler to the end of the conical section, which makes it progressively more difficult to insert the first end of the coupler into the end of the tubing. If this process is done by hand, it can be difficult and time consuming to fully seat the first end of the coupler into the end of the tubing.
The third problem pertains to the insertion of the second end of the coupler into the hole formed in the distribution tubing, as described above. The coupler is retained to the distribution tubing by an interference fit between the edges of the newly formed hole and the outside diameter of the second end of the coupler which is typically identical to the first end of the coupler having a conical configuration. Typically the second end of the coupler is stabbed into the newly formed hole and manually pushed until the large conical end is enveloped within the edges defining the opening. Ideally, the coupler will be inserted sufficiently deep that the trailing edge of the conical section will seal against the inside wall of the distribution tubing. However, the lip of displaced material around the inside edge of the opening may prevent such a seal, resulting in leakage around the coupler. Applying sufficient pressure to properly seat the coupler can be difficult, particularly when the coupler is installed manually. For large installations, where thousands of couplers may be required, the problem is manifested by either a significant expenditure of time to properly install the couplers, a number of incorrectly installed couplers resulting in leakage, or a combination of both of these undesirable events.